Project 3 (fMRI) will gather functional magnetic resonance imaging measures in two cohorts of subjects, in order to determine early prognostic factors for the development of Alzheimer's disease (AD). Both cohorts will consist of controls (CDR=0) and subjects with "questionable" AD (CDR=0.05). Participants will be evaluated at Baseline (Time 1) by fMRI and will be followed to determine changes in functional status. A subset will also be reevaluated at a second time point. At both assessments, Project 3 will utilize a memory task to activate specific brain systems and detect these changes with fMRI. Based on findings from within the Program Project, as well as from findings in the literature, it is hypothesized that fMRI measurements in selected brain regions (e.e., the hippocampal formation, the anterior and posterior cingulate, the anterior thalamus and prefrontal regions) will be prognostic markers of which "questionable" subjects develop AD over time. We will also examine the relationship between fMRI and measures from the other Projects, including neuropsychological test scores, single photon emission computed tomography (SPECT) and genetic data.